Continuous hydrostatic extrusion-drawing apparatus

ABSTRACT

Herein disclosed is a continuous hydrostatic extrusion-drawing apparatus comprising a main body housing defining a wire passage, in which a working fluid under pressure is confined and through which a wire is made to continuously pass for extrusion and drawal at a high reduction ratio. The present apparatus further comprises a first die disposed at the inlet of said wire passage and formed with a bore having an effective diameter, which is smaller than that of a fed wire, a second die disposed at the outlet of said wire passage and formed with a bore having an effective diameter, which is smaller than that of the first-named die, pulling means disposed midway of said wire passage for continuously pulling the fed wire through the first-named die to such an extent as to overcome the back tension, which is exerted on the passing wire due to the difference in the effective diameter between the first- and second-named dies, and take-up means disposed outside of said main body housing for continuously pulling the once-pulled wire through the second-named die in synchronism with said pulling means to such an extent as to afford a predetermined front tension to said once-pulled wire and for concurrently taking up the twice-pulled wire thereon. The present apparatus can be appreciated not only in its capability of accomplishing continuous extrusion-drawing of a wire at a high reduction ratio but also in the resultant elongation of life time of the dies used. The apparatus can also be appreciated in its simplicity of handling and construction.

United States Patent [191 Hayashi et al.

[ Mar. 18,1975

[ CONTINUOUS HYDROSTATIC EXTRUSlON-DRAWING APPARATUS [75] Inventors: Makoto Hayashi; Masanori Hinata,

both of Osaka, Japan [73] Assignee: Sumitomo Electric Industries, Ltd.,

Osaka, Japan 221 Filed: Dec. 17, 1973 21 Appl. No.: 425,650

[30] Foreign Application Priority Data UNITED STATES PATENTS 524,509 8/1894 Robertson 72/60 3,328,998 7/1967 Sabroff et al. 72/60 3,740,985 6/1973 Fuchs, Jr. 72/60 Primary ExaminerRichard J. Herbst Attorney, Agent, or Firm-Sughrue, Rothwell, Mion, Zinn & Macpeak 571 ABSTRACT Herein disclosed is a continuous hydrostatic extrusiondrawing apparatus comprising a main body housing defining a wire passage, in which a working fluid under pressure is confined and through which a wire is made to continuously pass for extrusion and drawal at a high reduction ratio. The present apparatus further comprises a first die disposed at the inlet of said wire passage and formed with a bore having an effective diameter, which is smaller than that of a fed wire, a second die disposed at the outlet of said wire passage and formed with a bore having an effective diameter, which is smaller than that of the first-named die, pulling means disposed midway of said wire passage for continuously pulling the fed wire through the firstnamed die to such an extent as to overcome the back tension, which is exerted on the passing wire due to the difference in the effective diameter between the firstand second-named dies, and take-up means disposed outside of said main body housing for continuously pulling the once-pulled wire through the secondnamed die in synchronism with said pulling means to such an extent as to afford a predetermined front tension to said once-pulled wire and for concurrently taking up the twice-pulled wire thereon. The present apparatus can be appreciated not only in its capability of accomplishing continuous extrusion-drawing of a wire at a high reduction ratio but also in the resultant elongation of life time of the dies used. The apparatus can also be appreciated in its simplicity of handling and construction.

3 Claims, 2 Drawing Figures CONTINUOUS HYDROSTATIC EXTRUSION-DRAWING APPARATUS BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an extrusion-drawing apparatus, and, more particularly, to a continuous hydrostatic extrusion-drawing apparatus comprising a main body housing defining a wire passage, in which a working fluid under pressure is confined and through which a wire is made to continuously pass for extrusion and drawal at a high reduction ratio.

2. Description of the Prior Art An ordinal reduction ratio available for a die of a current drawing process is known to fall in about This reduction ratio could be raisedemperically up to about but the ratio higher than 30 would invite breakage of the wire. Moreover, such excessive increase in the reduction ratio would invite shortening'of life time of the used die.

As a successful tactic for increasing the reduction ratio, on the other hand, a hydrostatic extrusion method is known in the art, in which a wire is extruded through a die under a high pressure built up around the wire by a pressurized working fluid. This method is characterized by the formation of a lubrication film of the working fluid between the die and the wire, so that it can be appreciated in considerable elongation of the die life time and in the desired high reduction ratio. These advantages are, however, offset by the fact that some suitable means is not available for feeding the wire to the extrusion apparatus from the outside and for continuously accomplishing the hydrostatic extrusion. In the conventional method, accordingly, a wire of a predetermined length is put in advance into a high pressure container. Thus, this method is necessarily carried out by the so-called batch operation, with the result of remarkable reduction in the working ratio.

SUMMARY OF THE INVENTION It is, therefore, a primary object of the present invention to provide a continuous hydrostatic extrusiondrawing apparatus, in which the afore-mentioned drawbacks concomitant with the prior art apparatus are eliminated and in which a wire continuously fed from the outside can be subjected to the hydrostatic extrusion at a high reduction ratio under a front tension weaker than the yield strength of the wire.

Another object of the present invention is to provide a continuous hydrostatic extrusion-drawing apparatus of the above type, in which the wire can be continuously supplied by such a capstan or the like, as is rotated in a high pressure container, against such a back tension as is exerted on the fed wire due to the pressure difference between the inner side and the outer side of the container.

Still another object is to provide a continuous hydrostatic extrusion-drawing apparatus of the above type, in which a lubrication film is formedof the pressurized working fluid between the wire and the dies to thereby lengthen the life time of the dies.

A further object is to provide a continuous hydrostatic extrusion-drawing apparatus of the above type, which enjoys an enhanced working ratio and simplicity of handling and construction.

According to a major feature of the present invention, a continuous hydrostatic extrusion-drawing apparatus is provided, which comprises a main body housing defining therein a wire passage, in which a working fluid under pressure is confined and through whicha wire to be extruded and drawn is made to pass, a first die disposed at the inlet of said 'wire passage and formed with a bore having an effective diameter which is smaller than that of a fed wire, a second die disposed at the outlet of said wire passage and formed with a bore having an effective diameter which is smaller than that of the first-named die, pulling means disposed midway of said wire passage for continuously pulling the fed wire through the first-named die to such an extent as to overcome the back tension which is exerted on the passing wire due to the difference in the effective diameter between the firstand second-named die, and take-up means disposed outside of said main body housing for continuously pulling the once-pulled wire through the second-named die in synchronism with said pulling means to such an extent as to afford a predetermined front tension to said once-pulled wire and for concurrently taking up the twice-pulled wire thereon.

BRIEF DESCRIPTION OF THE DRAWINGS DESCRIPTION OF THE PREFERRED EMBODIMENT One embodiment of the present invention will be described with reference to the accompanying drawings, but it should be understood that the present invention should not be limited to the particular embodiment but can have a variety of modifications without departing from the concept andspirit thereof.

Indicated at reference numerals 8 and 8' are halves of a main body housing, between which a capstan room A having a larger space than a capstan l is formed. A piping room B is also formed in between, which has its axis arranged in the tangential direction with the periphery of the capstan 1. These two rooms A and B constitute themselves a wire passage, through which a wire to be extruded and drawn is made to pass. The housing halves 8 and 8' are fastened to each other by a suitable number of bolts 9 with the capstan 1 being equiped in the capstan room A. The upper and lower ends of the housing halves 8 and 8' are also fastened to outer frames 10 and 10' by means of bolts 18. At the inlet and outlet of the housing halves 8 and 8 are disposed dies 2 and 3, respectively, which are firmly retained thereat by die stoppers 4 and 5. On the other hand, a pressure conduit 6 is formed in the housing halves 8 and 8' so as to introduce a working fluid under pressure into the capstan roomA and the piping room B. As bettending end of the driving shaft 13 is attached a sprocket wheel 14, which is driven through a chain 17 by a sprocket wheel attached to the output shaft of an electric motor 16. This electric motor 16 may preferably be of the type having its speed easily controllable, since it has to. rotate in synchronism with a suitable take-up mechanism (not shown). In a modification, moreover, the electric motor 16 may be dispensed with, in which case the driving shaft 13 is driven by a prime mover for the take-up mechanism through a suitable reduction gear mechanism. Although the capstan 1 shown as a pulling mechanism is one in number, the pulling mechanism may include a plurality of similar capstans, if desired.

The operation of the present apparatus thus constructed will now be described in the following. At first, a wire 7 having a diameter slightly larger than an effective diameter of the inlet die 2 is drawn through the die stopper 4 by the die 2 into a wire portion 7', which is shaped to have the same diameter as that of the inlet die 2. The wire portion 7' thus shaped is then pulled by and wound on the capstan 1 at least once to be drawn to the outside through the outlet die 3 and the die stopper 5. in this instance, it should be noted that the effective diameter of the oultet die 3 is made considerably smaller than the once-pulled wire portion 7', and accordingly that its reduction ratio a is much higher than the reduction ratio B from the wire 7 to the wire portion 7'.

Due to the difference in the effective diameter between the inlet and outlet dies 2 and 3, an undesirable back tension is exerted on the passing wire portion 7' when the pressurized working fluid is forced into the capstan room A and the piping room B through the pressure conduit 6. The back tension F is directed toward the inlet side, and is expressed by a product of the pressure P of the working fluid and the difference between the effective areas S and S of the two dies 2 and 3, namely, by a formula F P (S S In accordance with the present invention, this back tension F can be overcome by the pulling force of the capstan 1 which is driven by the electric motor 16 through the sprocket wheel 15, the chain 17, the sprocket wheel 14 and the driving shaft 13. In accordance with the present invention, moreover, a predetermined front tension can be afforded to a wire portion 7" by a suitable take-up mechanism such as a spool, so that the wire can be subjected tothe continuous extrusion-drawing at the high reduction ratio a.

If, in this instance, the back tension F is left as it is, such a relationship as follows is obtainable:

where 6 indicates a drawing stress of the wire portion 7 If, moreover, the ratio of the effective areas of the dies 2 and 3, namely, 5 /8 is 3, then a formula P 6/2 is obtained. Since, in this instance, the drawing stress 8 has an order of 40 kg/mm for the wire 7 made of hard copper, the resultant pressure P to be exerted on the working fluid is less than 2000 kg/cm From the practical consideration, however, the allowable tensile stress cannot exceed a half of the yield strength of the wire 7, and accordingly the allowable maximum level of the pressure P is about 1000 kg/cm From the experiments conducted by us, the ratio 5 /8 of the die effective areas is found of the order of 1.5 for P 1000 kglcm For the wire having a larger drawing stress 6, it is preferable that the extrusion and drawing should be accomplished under a higher pressure than the level of 2000 kg/cm Here, it should be noted that the main body housing need not be limited to the afore-mentioned type having the two rooms-A and B but can have a relatively large volume such as an autoclave.

Representative experimental conditions will now be enumerated in the following:

EXAMPLE Material for Wire Soft Copper Diameter of Fed Wire 0.9 mm Diameter of Inlet Die 0.89 mm Diameter of Outlet Die 0.64 mm Fluid Pressure 1500 kg/cm Front Tension 20 kg/mm Drawing Speed 300 m/minute Inlet Reduction Ratio B 2 Outlet Reduction Ratio a 47 7:

As has been described in the above, a continuous hydrostatic extrusion-drawing apparatus according to the present inventionis characterized by the provision of a main body housing defining therein a wire passage, in which a working fluid under pressure is confined and through which a wire to be extruded and drawn is made to pass, of a first die disposed at the inlet of said wire passage and formed with a bore having an effective diameter which is smaller than that of a fed wire, of a second die disposed at the outlet of said wire passage and formed with a bore having an effective diameter which is smaller than of the first-named die, of pulling means disposed midway of said wire passage for continuously pulling the fed wire through the first-named die to such an extent as to overcome the back tension which is exerted on the passing wire due to the difference in the effective diameter between the firstand secondnamed dies, and of take-up means disposed outside of said main body housing for continuously pulling the once-pulled wire through the second-named die in synchronism with said pulling means to such an extent as to afford a predetermined front tension to said oncepulled wire and for concurrently taking up the twicepulled wire thereon.

With the above construction arrangements, therefore, the present apparatus should be appreciated not only in its capability of accomplishing continuous extrusion-drawing of a wire at a high reduction ratio but also in the resultant elongation of life time of the dies used. The apparatus should also be appreciated in its simplicity of handling and construction, with the resultantly enhanced working ratio. The apparatus should further be appreciated in its augmented reduction ratio for one die, and this feature is the most prominent where it is applied to extrusion-drawing of a composite wire. From these reasonings, it will be understood that the present apparatus can find a wide variety of industrial applications.

What is claimed is:

l. A continuous hydrostatic extrusion-drawing apparatus comprising:

a main body housing defining therein a wire passage, in which a working fluid under pressure is confined and through which a wire to be extruded and drawn is made to pass;

a first die disposed at the inlet of said wire passage and formed with a bore having an effective diameter which is smaller than that of a fed wire;

a second die disposed at the outlet of said wire passage and formed with a bore having an effective diameter which is smaller than that of the first-named die;

pulling means disposed within said working fluid midway of said wire passage and directly frictionally gripping said wire for continuously pulling the fed wire through the first-named die to such an extent as to overcome the back tension which is exerted on the passing wire due to the difference in the effective diameter between the firstand secondnamed dies; and

take-up means disposed outside of said main body housing for continuously pulling the once-pulled wire through the second-named die in synchronism determined level. 

1. A continuous hydrostatic extrusion-drawing apparatus comprising: a main body housing defining therein a wire passage, in which a working fluid under pressure is confined and through which a wire to be extruded and drawn is made to pass; a first die disposed at the inlet of said wire passage and formed with a bore having an effective diameter which is smaller than that of a fed wire; a second die disposed at the outlet of said wire passage and formed with a bore having an effective diameter which is smaller than that of the first-named die; pulling means disposed within said working fluid midway of said wire passage and directly frictionally gripping said wire for continuously pulling the fed wire through thE first-named die to such an extent as to overcome the back tension which is exerted on the passing wire due to the difference in the effective diameter between the first- and second-named dies; and take-up means disposed outside of said main body housing for continuously pulling the once-pulled wire through the secondnamed die in synchronism with said pulling means and acting to such an extent as to afford a predetermined front tension to said once-pulled wire and for concurrently taking up the twicepulled wire thereon.
 2. A continuous hydrostatic extrusion-drawing apparatus according to claim 1, wherein said pulling means includes at least one capstan on which the once-pulled wire is wound.
 3. A continuous hydrostatic extrusion-drawing apparatus according to claim 1, further comprising fluid feed means for feeding the working fluid into said wire passage so as to maintain the pressure therein at a predetermined level. 